442 



THE INDIA RUBBER WORLD 



[August 1, 1911. 



A RUBBER TESTING HYSTERESIS MACHINE. 



This iniportam little machine is llie invention of I'rof. .Mired 

 Schwartz, a noted English professor of physics and electrical 

 engineering, .^s seen in the ilUistration the machine shows the 



Mai 



Rubber Testing Hvstere.--is M.\chi.ne. 



effect of the e.xtension of a piece of rnbber by means of a load 

 which is increased at a regular rate until either load of e.xpan- 

 sion is attained. When this has been done the load is diminished 

 at a given rate, the rubber allowed to retract and the relation 



D 



panying diagram. This, by the way, is drawn upon a sheet of 

 paper attached to a moving table. The line O B is made 

 during extension and is the result of the stretch of the rubber 

 and of a calibrated spring. D B is the retraction curve. The 

 outlines of the curve indicate the physical properties of the 

 rubber sample and thus determine its qualities and insulating 

 values. [Manufactured by G. Cnssons, Limited, Broughton, 

 Manchester, England.] 



E.xr,*»nc n^ 



between load and elongation is found to liave been recorded 

 automatically by a pen which draws two lines, one during ex- 

 tension and the other during retraction. It is exceedingly simple 

 and any one familiar with testing machines can see at a glance 

 its method of working. 



What is known as the hysteresis loop is shown in the accom- 



RUBBER LIMES FOR FISHING. 



To THE Editor of the Indi.\ Rubber World: 



Sir. — .As you are doubtless aware Cape Cod fishermen use a 

 long coiled spring of the best steel at one end of which the hook 

 in cod fishing is attached. The cod is likely to be a trifle unruly 

 when hooked, stretching the spring to its full tension. Tiring 

 eventually and weakened by its struggles, the spring recovers, 

 throwing the fish with violence from the water, frequently en- 

 dangering the life of the fisherman, who naturally becomes an 

 expert dodger. A land lubber at this sport is liable to black 

 eyes and missing teeth, for when the "sacred cod" lands, he lands 

 hard. 



I have given the dangerous nature of this sport close attention 

 in the last few weeks, and have evolved a remedy that will 

 revolutionize the methods long employed in the capture of fish, 

 and add a novelty to the rubber factory product ; in short, a 

 rubber fish line. 



I took twenty-five feet red tubing, containing 40 per cent. 

 "unrecovered fine Para" (see specifications for wire insulation 

 for particulars) and attached thereto a hook in the usual 

 manner. I also had the foresight to take the July issue of 

 The Indi.\ Rubber World, and thus equipped, proceeded to the 

 lair of the cod. The day was hot and the bay calm, and the 

 fishing being the reverse of exciting, I fell to reading. I must 

 have fallen into a pool of deep thought, for I was aroused by 

 the violent rocking of the boat. Whipping back and forth through 

 the water went the rubber line, now here, now there, and gazing 

 into the depths of the translucent ocean I saw an immense fish 

 in a frenzy of wrath. He would dive far below and the inexor- 

 able, elastic line would lengthen out and out, from 2S feet to 75 

 feet (you will observe if you consult specifications that it must 

 stretch four times its length without breaking), then tired with 

 its labors, relax and be steadily drawn back, not violently, as with 

 the spring contrivance referred to, but gently, inexorably, as is 

 the nature of a high-grade Para product. Then resting, the 

 fish made another wild rush for freedom until, finally, quivering 

 in every fiber of its magnificent length, it floated slowly to the 

 side of the boat and gasped. "What is this thing I've been pulling 

 on for the last half hour?" "A rubber line," I replied, gravely. 

 "Take me out — I thought it was an angle worm !" 



James W. C.\rey. 



Spider Lodge, Monument Point, Mass., July 4, 1911. 



ELECTRICIANS' GLOVES AND BOOTS. 



Prominent amongst tlie varied products of Harburg and 

 Vienna India Rnbber Co. is a line of special interest to electricians 

 and electrical workers. The rubber gloves and boots made by 

 this company, and guaranteed to withstand 20.000 volts, so effi- 

 ciently protect the wearers that no shock is felt when actually 

 holding live wires carrying high voltages. 



A WISE PRECAtrXION. 



Would-Be Customer — I want a good supply of shock-absorb- 

 ers — largest you've got. 



Rubber Dealer — What machine do you want them for? 



Customer — No machine; want them for myself. I'm going to 

 Atlantic City. 



